Spatially resolved distribution of dislocations and crystallographic tilts in GaN layers grown on Si(111) substrates by maskless cantilever epitaxy

Journal Article · Sun Jan 01 00:00:00 EST 2006 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2234807· OSTI ID:1003316

Barabash, Rozaliya ^[1]; Roder, C. ^[2]; Ice, Gene E ^[1]; Einfeldt, S. ^[2]; Budai, John D ^[1]; Barabash, Oleg M ^[1]; Figge, S. ^[2]; Hommel, D. ^[2]

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1. ORNL
2. University of Bremen, Bremen, Germany

The spatial distribution of strain, misfit and threading dislocations, and crystallographic orientation in uncoalesced GaN layers grown on Si(111) substrates by maskless cantilever epitaxy was studied by polychromatic x-ray microdiffraction, high-resolution monochromatic x-ray diffraction and scanning electron microscopy. Tilt boundaries formed at the column/wing interface depending on the growth conditions. A higher lateral to vertical growth ratio suppressed sidewall deposition and was found to produce larger lattice tilts in the GaN films. Two kinds of crystallographic tilts are observed in the films. The measurements revealed that the free-hanging wings are tilted upward at room temperature in the direction perpendicular to the stripes. Finite element simulations of the thermally induced part of the wing tilt are presented. Moreover, a misorientation between the GaN(0001) and the Si(111) planes is observed in the parallel to the stripes direction. Its origin is discussed with respect to the strain of the epitaxial GaN on a miscut Si(111) surface and misfit dislocations formed at the interface.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1003316
• Journal Information: Journal of Applied Physics, Vol. 100, Issue 5; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

characterization
GaN
dislocations
crystallographic tilts